Techniques for preoperative planning and postoperative evaluation of noncemented hip arthroplasty

A technique is standardized from which the funnel shape of the intramedullary canal and quality of cortical bone of the proximal femur can be measured on prcopenuive radiographs. The same points of measurement are used to calculate the percentage fill of noncemented femoral components. A cadaveric study was undertaken to test the validity of this radiographic technique Bone stock was qualitatively assessed from 100 radiographs as type A, B, or C and quantitatively by calculating the cortical index, which is the determination of the relative thickness of cortical bone. Type A bone had an average calcar-to-canal isthmus (CC) ratio of .56 with a cortical index of .59 on the anteroposterior (AP) and .53 on the lateral radiographs. Type B bone had an average CC ratio of .39 with a cortical index of .51 on the AP and .4-1 on the lateral radiographs. Type C bone had a CC ratio of .65 with a cortical index of A1 on the AP and .29 on the lateral radiographs. The lateral radiograph may yield information critical to the clinician in preopcrative planning. The stem-bone ratio statistically correlated with bone type and was .-13 on the AP and AI on the lateral for type A bone, .-19 on the AP and A4 on the lateral for type B bone, and .53 on the AP and AS on the lateral radiographs for type C bone. By using a simple standardized technique, the surgeon will be able to predict the outcome of noncemented femoral components and provide a common ground for comparing the results of noncemented hip arthroplasties.